Imaging device and method of manufacturing the same
In an imaging device having a waveguide, a surface of an insulating film covering a seal ring is prevented from getting rough. A pixel region, a peripheral circuit region, and a seal region are defined over a semiconductor substrate. After formation of a pad electrode in the peripheral circuit region and a seal ring in the seal ring region, a TEOS film is so formed as to cover the pad electrode and the seal ring. A pattern of a photoresist for exposing a portion of the TEOS film covering the pad electrode and the seal ring, respectively, is formed and etching treatment is subjected to the exposed TEOS film. Then, after the pattern of the photoresist has been formed, a second waveguide holding hole is formed in the pixel region by performing etching treatment.
1. A solid-state image sensing device, comprising:
a semiconductor substrate having a main surface,
a pixel region including a plurality of pixels formed on the main surface of the semiconductor substrate,
a peripheral circuit region formed outside of the pixel region,
a seal ring region including a seal ring formed outside of the peripheral circuit region and continuously enclosing the pixel region and the peripheral region,
a protective insulating film formed to cover the pixel region, the peripheral circuit region, and the seal ring region, and
a groove formed over the seal ring without penetrating through the protective insulating film, wherein
in a plan view, a width of the groove is larger than a width of the top part of the seal ring, and
in a direction perpendicular to an extending direction of the seal ring, the center of the groove is displaced outside of the center of the seal ring, and the groove is formed directly over the seal ring and covers the entire top part of the seal ring in a plan view.
2. A solid-state image sensing device according to claim 1 , wherein
a first concave portion is formed along the seal ring in the groove located outside of the seal ring in the protective insulating film, and
when a position of a surface of the protective insulating film located immediately above the seal ring is a first position, a position of the surface of the protective insulating film located in the first concave portion is a second position, and a position of the surface of the protective insulating film located in a direction departing from the first concave portion for the outside of the seal ring region is a third position, the second position is lower than the first position in height, and the third position is lower than the first position but higher than the second position in height.
3. A solid-state image sensing device according to claim 1 , wherein
the groove is formed over a whole of the seal ring region.
4. A solid-state image sensing device according to claim 2 , wherein
a second concave portion is formed along the seal ring in a region located on the inward side of the seal ring in the protective insulating film, and
a width of the first concave portion is greater than a width of the second concave portion.
5. A solid-state image sensing device according to claim 1 , wherein
a pad electrode is formed in the peripheral circuit region,
the protective insulating film includes a portion covering the pad electrode, and
thickness of a portion of the protective insulating film located immediately above the pad electrode is the same as that of a portion of the protective insulating film located immediately above the seal ring.
6. A solid-state image sensing device according to claim 5 , wherein
a plurality of interlayer insulation films are formed on the pixel region, the peripheral circuit region at a layer below the pad electrode, and the seal ring region at a layer below the top part of the seal ring,
in the pixel region, at least one of the plurality of interlayer insulating films is removed, and
a height on the pixel region of the surface of the protective insulating film from the main surface is lower than a height on a seal ring region thereof.
7. A solid-state image sensing device according to claim 1 , wherein
a plurality of waveguides are formed on the pixel region.